We plan to continue the development of general methods which will be generally applicable in the synthesis of macrolides, including the prototypes of the major subclasses within the group, partly in the hope that the presently obscure relationships between chemical structure and physiological activity in this important group might be elucidated. Fundamental advances made during the course of our exploratory studies have permitted us to define a relatively specific path for the synthesis of erythromycin - perhaps the most important of the macrolides; this path will be pursued with special vigor.